Control mechanisms underlying pathological and normal feeding behaviors will be examined in six areas using sham operated rats, rats with lateral hypothalamic damage, and rats with ventromedial hypothalamic damage as subjects. (1) Meal patterns of normal and brain damaged rats with and without vagotomy will be analyzed. (2) Oropharyngeal functions will be examined through the use of an intragastric feeding technique and through attempts to condition taste preferences. (3) Gastric function will be examind by studying the effects of vagotomy, effects of gastric loading, effects of removal of stomach contents during feeding. (4) Duodenal or other intestinal controls will be examined using infusions through intraduodenal catheters and systemic and intravenous administration of cholecystokinin, a presumptive satiety hormone from the duodenum. (5) Blood nutrient controls will be examined by intravenous infusion of nutrients during 24 hours, during spontaneous meals, or self-controlled infusions. (6) Motivational and regulatory deficits will be examined using operant techniques. An examination will be made of specific anatomical loci which might be responsible for one specific regulatory deficit.